Simple APM 2560 Power Hack

I'm constantly loading and testing code and the power setup of the 2560 can be a bit of a pain. Mainly, the radio does not receive power because the Servo rails are only powered via a Lipo, which can be very dangerous. I never do anything but fly with a Lipo connected and I certainly don't connect one indoors. I'm just paranoid that way.

This hack will power the radio half of the servo rail with 5V from the APM's USB connection. The idea is to spilt the 5V rail into two halves. If you use an X-Acto knife you can easily cut the trace connecting both sides. I cut the ground rail in half as well, then used some solder to repair the bridge. Then I connected the 5v from the APM to the input side as indicated below. Now I can power the radio with the USB.

Glenn maybe your confused by the numbering of the pins. On the older APMs boards the first pin was numbered 0 then through to 7 which is the eight pins for in put and eight pins for output on each side. The newer APMs the first pin is now numbered 1 then through to 8. Just make sure the cut is exactly in the middle of the 8 pins on each side which ever the numbering is.

Hi, not quite the same topic but related: How can it be that my APM1 does not power up or light any LEDs when powered from the BLCs when my friend's one does?

It runs OK when connected to, and presumably also powered from USB.

5V output from the BLC was verified with a meter, is OK. Also the plugs the correct way around (under both BLC and US power it will start its motors).

In the schematic (APM, not the oilpan), I see 4 different nodes with power on: +5V, +5V!, Vcc and JP17 Pin 2. I wonder which one is the USB one?

Both my own board and my friend's were bought completely assembled. Could there be a jumper wire somewhere that was omitted on mine? Is there a regulator between BLC power (which might really be 6V or more from some BLCs) and +5V?

where is SJ1? I did this mod Dave and didn't unsolder anything. Just make sure you do the clean cut of the copper trace between input and out put side. I was using the ESC power and it worked fine but now I'm using a separate switching 5v 3amp regulator power supply.